This study will determine the most effective treatment strategy for infertile couples who present when the female partner is 40-43 years old and are determined to have a reasonable chance for success. We will conduct a randomized clinical trial to compare success rates and costs. Eligible couples will be randomized to one of three treatment arms: four cycles of immediate in vitro fertilization (IVF), two cycles of clomiphene/intrauterine insemination (IUI) followed by four cycles of IVF, or two cycles of FSH/IUI followed by four cycles of IVF. Visits for infertility services by women of advanced reproductive age have increased disproportionately to those of younger women. Natural fecundity decreases markedly after age 40 because of a decrease in the number of viable oocytes within the ovaries and an increasing proportion of chromosomal abnormalities in those that remain. Success rates for fertility treatment using their own oocytes are significantly lower for older couples. However, for those with adequate ovarian function, achieving pregnancy may be possible before turning to alternative means of building a family. 1,500 deliveries were reported nationwide in the 1999 CDC National Summary and Fertility Clinics Report for this age group. Very few studies exist in conventional treatments that include the use of superovulation and IUI (SO/IUI) with either clomiphene (an oral medication) or injectable gonadotropins. Although it is likely that these treatments do not differ in success, an unproven bias exists against the less expensive of the two. No randomized trials comparing SO/IUI with IVF in older couples with a reasonable ovarian reserve have been performed. IVF success rates for these couples are higher than the rates reported from small studies using SO/IUI. The proposed study takes advantage of two local features: (1) BIDMC/Boston IVF is the largest infertility center in the United States, treating over 3,084 new patient couples each year, 509 of whom the female partner is 40-43, and performing nearly 6% of all US IVF procedures for this age group; and, (2) insurance coverage for infertility is required by Massachusetts law for all participants. The choice of therapeutic alternatives is unaffected by the patient's ability to pay for treatment. [unreadable] [unreadable]